PCAP_FINDALLDEVS
Section: Misc. Reference Manual Pages (3PCAP)
Updated: 5 April 2008
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NAME
pcap_findalldevs - get a list of capture devices
SYNOPSIS
#include <pcap/pcap.h>
char errbuf[PCAP_ERRBUF_SIZE];
int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);
DESCRIPTION
pcap_findalldevs()
constructs a list of network devices that can be opened with
pcap_create()
and
pcap_activate()
or with
pcap_open_live().
(Note that there may be network devices that cannot be opened by the
process calling
pcap_findalldevs(),
because, for example, that process might not have sufficient privileges
to open them for capturing; if so, those devices will not appear on the
list.)
alldevsp
is set to point to the first element of the list; each element of the
list is of type
pcap_if_t,
and has the following members:
-
- next
-
if not
NULL,
a pointer to the next element in the list;
NULL
for the last element of the list
- name
-
a pointer to a string giving a name for the device to pass to
pcap_open_live()
- description
-
if not
NULL,
a pointer to a string giving a human-readable description of the device
- addresses
-
a pointer to the first element of a list of addresses for the interface
- flags
-
interface flags:
-
- PCAP_IF_LOOPBACK
-
set if the interface is a loopback interface
Each element of the list of addresses is of type
pcap_addr_t,
and has the following members:
-
- next
-
if not
NULL,
a pointer to the next element in the list;
NULL
for the last element of the list
- addr
-
a pointer to a
struct sockaddr
containing an address
- netmask
-
if not
NULL,
a pointer to a
struct sockaddr
that contains the netmask corresponding to the address pointed to by
addr
- broadaddr
-
if not
NULL,
a pointer to a
struct sockaddr
that contains the broadcast address corresponding to the address pointed
to by
addr;
may be null if the interface doesn't support broadcasts
- dstaddr
-
if not
NULL,
a pointer to a
struct sockaddr
that contains the destination address corresponding to the address pointed
to by
addr;
may be null if the interface isn't a point-to-point interface
Note that not all the addresses in the list of addresses are
necessarily IPv4 or IPv6 addresses - you must check the
sa_family
member of the
struct sockaddr
before interpreting the contents of the address.
The list of devices must be freed with
pcap_freealldevs().
RETURN VALUE
pcap_findalldevs()
returns 0 on success and -1 on failure.
If -1 is returned,
errbuf
is filled in with an appropriate error message.
errbuf
is assumed to be able to hold at least
PCAP_ERRBUF_SIZE
chars.
SEE ALSO
pcap(3PCAP), pcap_create(3PCAP), pcap_activate(3PCAP),
pcap_open_live(3PCAP), pcap_freealldevs(3PCAP)